It is standard practice in the spinning of yarn or thread to draw out one or more slivers of fibers, typically cotton ones, in a drawing frame formed by a plurality of pairs of rollers. These roller pairs are spaced apart in the travel direction of the filaments or sliver and are rotated at speeds that increase upstream to downstream, with the furthest downstream roller pair rotating at a peripheral speed that is a multiple of that of the upstream pair, typically by a factor equal to the number of slivers that are being combined.
In a standard system the furthest downstream roller pair is not displaceable in the travel direction, but is mounted directly on the spinning apparatus for rotation about a fixed axis. The other roller pairs are carried in journal blocks slidable in the travel direction on a rail extending in the travel direction. Means is provided for locking these slidable journal blocks in place on the rail at spacings determined by the staple length of the fiber being drawn and other factors.
In a standard system described in Die moderne Baumwollspinnerei by Fritz Walz (Bernh. Friedr. Voigt Verlag, Berlin-Hamburg, page 267) an arrangement is described wherein the furthest downstream roller pair is fixed on the ring spinner frame and the lower roller of each of the roller pairs upstream therefrom is connected via a respective telescoping shaft and two universal joints to the respective output shaft of the drive. In this manner rotation is transmitted from the transmission output shafts to the respective roller pairs irrespective of their relative positions.
This arrangement is disadvantageous in that the entire drive arrangement must be relatively long to prevent the universal shafts from having to compensate for severe angular offsets. In addition the universal joints do not transmit torque smoothly, and are not capable of operating at high speeds over long periods of time.